Means for extinguishing burning motion picture films



Jan. 23, 1940. J. J. SHERWOOD El AL 2,137,988

MEANS FOR EXTINGUISHING BURNING MOTION PICTURE FILMS Filed May 29, 1939 In D El n u u El// :1 D n n u DDDEIDDDUDDCID 4 INVENTORS JOSEPH JSHERWOOD FRANK A.PENTLAND ATTORNEY Patented Jan. 23, 1940 UNITED STATES PATENT OFFICE MEANS FOR EXTINGUISHING BURNING MOTION PICTURE FILMS Application May 29, 1939, Serial No. 276,278

12 Claims.

This invention relates generally to fire prevention means and more specifically to improved means for extinguishing fire in connection with motion picture fflm passing through projecting apparatus, the predominant object of the invention being to provide improved means which serves to quickly and effectively extinguish such a fire so as to confine the damage to a comparatively small section of the film, and also to greatly minimize the dangers of alarm and panic which might be occasioned among the spectators in a theatreby even a harmless blaze.

As is quite generally known to persons familiar with such matters, motion picture films are made from material of a highly inflammable nature, and as a result of this fact there is an everpresent danger of fire when a film is being projected if for any reason movement of the film is arrested due to sticking of the film, or for any other cause. In such a situation the film is usually ignited, unless this is prevented by some eflicient and quick-acting means, due to the contact of the direct rays of the projecting light with the stationary film.

Prior to this invention means have been employed in association with motion picture projecting machines which includes each a shield adapted to be automatically dropped into a position where it shields the film from the direct rays of the projecting light in the event movement of the film through the projecting machine is arrested for any reason. However, because of the highly inflammable nature of the film there is always a danger that the film will be ignited before the shield moves to its protective position, and when this happens the entire film is exposed to the fire with the resultant danger that other films, or other articles, within the projection booth Will be set afire by the quick-burning film. The purpose of the present invention, therefore, is to provide improved means which, in the event a film moving through a projecting machine becomes ignited for any reason, will promptly and effectively extinguish I the blaze before the flame has an opportunity to spread to other parts of the film or to other films, or other articles in the projecting booth.

Fig. 1 is a diagrammatical view illustrating the invention.

Fig. 2 is a diagrammatical view of a modified form of the invention as illustrated in Fig. 1.

Fig. 3 is a vertical section taken through the supply reel from which the film is withdrawn for passage through the light field of the projecting machine showing the film and the protective ribbon wound thereon.

Fig. 4 is a fragmentary view showing sections of a film and the associated. protective ribbon in the relative positions they occupy when wound on a reel.

Fig. 5 is an enlarged fragmentary vertical section taken through the reel illustrated in Fig. 3.

In the drawing, wherein are shown for the purpose of illustration, merely, two embodiments of the invention, A designates a supply reel on which a film B is wound spirally in the usual manner, said film B being unwound from the reel A by a pair of sprocket wheels C and said film being drawn vertically through the light field of the projecting machine by a pair of sprocket wheels D and being wound on a take-off reel E. The sprocket wheels C and D and the take-ofi reel E are driven in the usual manner by an electric motor (not shown) which is ordinarily associated with a projecting machine for this purpose.

Wound on the supply reel A with the film- B is a protective ribbon I which'is formed from any suitable noninfiammable material such, for instance, as metal, or asbestos, said protective ribbon being slightly wider than the film as shown to the best advantage in Figs. 4 and 5. In winding the film B and protective ribbon l on the reel A said film and protective ribbon are arranged in contact with each other as shown in Fig. 4 and the associated film and protective ribbon are wound spirally on the reel as shown in Fig. 3. In this way substantially the entire surfaces of the film will contact with portions of the protective ribbon and all of the turns of the film, with the exception of the innermost turns, will be interposed between two turns of the protective ribbon (see Fig. 5). When the film B is unwound from the supply reel A by the sprocket wheels C and D the protective ribbon I is likewise unwound from said supply reel and is wound on a take-off reel F provided for the reception of the protective ribbon. Also as the film B is wound on the take-oif reel E after passage thereof through the light field of the projecting machine a second protective ribbon l' is Wound on said take-off reel E with the film, the arrangement of winding of the film and protective ribbon I on the take-off reel E being the same as that already described in connection with the winding of the film and protective ribbon l on the supply reel A. The protective ribbon l which is wound on the take-off reel E with the film B as described, is unwound from a ribbon supply reel G, said ribbon supply reel G either being driven by the electric motor which drives the sprocket wheels C and D and the take-off reel E, or being mounted for free rotation with a spring G associated therewith for maintaining the protective ribbon in a taut condition as it passes to the take-01f reel E. The supply reel A and the ribbon take-ofi reel F are driven by an electric motor H distinct from the motor of the projecting machine which drives the sprocket wheels C and D and the take-oil reel E, said motor H being the reversing type.

In Fig. 1, J, K, and L represent the usual lenses which provide the optical projecting system of the projecting machine illustrated diagrammatically in that view, and these lenses serve to project a light beam M from a light source (not shown) that creates a light field through which the film B is moved for projecting the images on the film onto a screen. So as to protect the film from the direct rays of the projecting light when movement of the film is arrested a mechanism is provided which includes a hood N mounted for pivotal movement at the point designated by the reference character P. The lower end of the hood N has pivotally connected thereto a link Q which at its opposite end is pivotally connected to an operating arm S of a reversing switch H electrically connecting with the motor H. The link Q is provided with an abutment Q that is adapted to engage an abutment T which is extended from a rotary element U, said element U having a light torsional coil spring U associated therewith in such manner that the torsional coil spring tends to rotate the element U. Also the element U has suitably fixed thereto a shield V.

The film B, as it passes from the sprocket wheels C, moves beneath the hood N and is guided vertically in a downward direction by the guide rollers W and the stationary guide X and, in the event movement of the film through the light field of the projecting machine is arrested for any reason, the film will build up beneath the hood because of the continued operation of the sprocket wheels C and this building up of the film beneath the hood will raise the upper portion of the hood. This will move the link Q to the right in Fig. 1 and when the link has moved far enough the abutment T on the element U will pass beneath the abutment Q on the link to permit the torsional coil spring U to swing the shield V to the lowered position in which it is shown by dotted lines in Fig. 1 where it will shield the stationary film from the direct rays of the projecting light. I

The mechanism just described for protecting a stationary film from the direct rays of the projecting light of a projecting machine is in general. use at the present time and because its arrangement and operation is well known to persons familiar with the art no attempt has been made to illustrate and describe the mechanism in all of its details. Instead the mechanism in question has been shown in a greatly simplified form and has been combined in a simple manner with the present invention so that a simple but complete understanding of the invention may be had.

When in the operation of a projecting machine constructed and arranged in accordance with the present invention, the movement of the film through the light field of the projecting machine is arrested and the film is ignited the building up of film beneath the hood N'Will raise the hood and permit the shield V to move to the position in which said shield is shown by dotted lines in Fig. 1. Also the movement to the right in Fig. 1 of the link Q as described will throw the reversing switch H to reverse the motor I-I whereby the portion of the film between the supply reel A and the point at which the film is burning, will be rewound with the protective ribbon l on said supply reel A with the result that the flame will be extinguished by being smothered by contact of the burning portion of the film with the protective ribbon. Additionally, the portion of the film between the point at which the film is burning and the take-01f reel E will be wound with the protective ribbon l on said take-off reel E by the continued operation of the motor associated with the projecting machine so as to extinguish in the same manner any portion of the latter portion of the film which might be burning.

In order to permit the sprocket wheels C to rotate in two directions ratchet and pawl asseinblies 2 are employed in association with said sprocket wheels. The pawls move with the shaft 0 when the projecting machine is being operated in a normal manner by its electric motor, and because of engagement of the pawls with the teeth of the ratchets associated with the sprocket wheels, the sprocket wheels C will be rotated in a clockwise direction to withdraw the film from the supply reel A, said supply reel also being operated in a clockwise direction but by the motor H. However, when the motor H is reversed by operation of the reversing switch H, as heretofore described to reverse the direction of rotation of the reels A and F, the direction of rotation of the sprocket wheels will be likewise reversed by the reverse movement of the film, the pawls during such reverse movement of the sprocket wheels C sliding idly over the teeth of the associated ratchets of the sprocket wheels.

In the event the shield V is dropped to its lowered protective position fast enough to prevent the film from igniting when movement of the film is arrested for any unintentional reason, the direction of rotation of the reels A and F will be reversed as has been previously explained herein with the result that the film will be broken. However, such breaks in films may be very easily and readily repaired.

Instead of employing the mechanical means for reversing the motor H as hereinbefore described and as illustrated in Fig. 1, said reversing of said motor H may be accomplished through the operation of thermo-switches Y as shown in Fig. 2. These heat-sensitive switches are disposed in locations in close proximity to the point at which the direct rays of the projecting light will ignite the stationary film, and when the film is ignited the excessive heat produced by the burning film will cause the heat-sensitive switches Y to be actuated to reverse the motor H and thereby extinguish the burning film as has been previously explained herein. If desired the heat-sensitive switches Y of Fig. 2 may be combined with the mechanical means of reversing the motor H as shown in Fig. 1 to provide both types of reversing meansin one projecting apparatus structure.

It is to be noted that the protective ribbons of the present invention are slightly wider than the films with which they are associated. By this arrangement the edges of the films are protected against mechanical blows and wear which may have a tendency to cause the edge portions of the films to break at the drivingnotches of the films.

We claim:

1. A motion picture projecting machine including a supply reel, a film and a strip of non-combustible material wound spirally on said supply reel with said film and said strip of non-combustible material in contact with each other throughout substantially their entire lengths, means for unwinding said film and said strip of non-combustible material from said supply reel, and means for rewinding said film and said strip of non-combustible material on said supply reel in the event portions of the film are separated by burning of the film.

2. A motion picture projecting machine including a supply reel, a film and a strip of noncombustible material wound spirally on said supply reel with said film and said strip of noncombustible material in contact with each other throughout substantially their entire lengths, means for unwinding said film and said strip of non-combustible material from said supply reel, a reel adapted to receive said strip of noncombustible material when same is unwound from said supply reel, and means for rewinding said film and said strip of non-combustible material on said supply reel in the event portions of the film are separated by burning of the film.

3. A motion picture projecting machine including a supply reel, a film and a strip of non-combustible material wound spirally on said supply reel with said film and said strip of non-combustible material in contact with each other throughout substantially their entire lengths, means for rewinding said film and said strip of non-combustible material from said supply reel, a reel adapted to receive said strip of non-combustible material when same is unwound from said supply reel, and means actuated in response to stoppage of the movement of said film through the light field of the projecting machine for rewinding said film and said strip of non-combustible material on said supply reel in the event portions of the film are separated by burning of the film.

4. A motion picture projecting machine including a supply reel, a film and a strip of noncombustible material wound spirally on said supply reel with said film and said strip of noncombustible material in contact with each other throughout substantially their entire lengths, said strip of non-combustible material being of greater width than said film, means for unwinding said film and said strip of non-combustible material from said supply reel, and means for rewinding said film and said strip of non-combustible material on said supply reel in the event portions of the film are separated by burning of the film.

5. A motion picture projecting machine including a supply reel, a film and a strip of noncombustible material wound spirally on said supply reel so that substantially all portions of the surfaces of said film are in contact with said strip of non-combustible material, means for unwinding said film from said supply reel, a takeofi reel adapted to receive said film, a second strip of non-combustible material which is wound spirally on said take-off reel with said film so that substantially all portions of the surfaces of the film move into contact with said second strip of non-combustible material, and means for reversing the direction of movement of a portion of said film in the event portions of said film are separated by burning of the film whereby a portion of the film moves in the normal direction to be wound spirally on said take-off reel with said second strip of non-combustible material while another portion of said film is rewound spirally on said supply reel with the first mentioned strip of non-combustible material.

6. A motion picture projecting machine including a supply reel, a film and a strip of noncombustible material wound spirally on said supply reel so that substantially all portions of the surfaces of said film are in contact with said strip of non-combustible material, means for unwinding said film from said supply reel, a takeoff reel adapted to receive said film, a second strip of non-combustible material which is wound spirally on said take-off reel with said film so that substantially all portions of the surfaces of the film move into contact with said second strip of non-combustible material, means for reversing the direction of movement of a portion of said film in the event portions of said film are separated by burning of the film whereby a portion of the film moves in the normal direction to be wound spirally on said take-off reel with said second strip of non-combustible material while another portion of said film is rewound spirally on said supply reel with the first mentioned strip of non-combustible material, a reel for receiving the first mentioned strip of non-combustible material, and a reel for receiving the second mentioned strip of non-combustible material.

7. A motion picture projecting machine including a supply reel, a film and a strip of noncombustible material wound spirally on said supply reel so that substantially all portions of the surfaces of said film are in contact with said strip of non-combustible material, a motor of the reversing type for actuating said supply reel, means for unwinding said film from said supply reel, a take-off reel adapted to receive said film, a second motor for actuating said unwinding means and said take-off reel, a second strip of non-combustible material which is wound spirally on said take-off reel with said film so that substantially all portions of the surfaces of the film move into contact with said second strip of noncombustible material, and means for reversing the first mentioned motor in the event portions of the film are separated by burning of the film whereby a portion of the film moves in normal direction to be wound spirally on said take-off reel with said second strip of non-combustible material while another portion of the film is rewound spirally on said supply reel with the first-mentioned strip of non-combustible material.

8. A motion picture projecting machine including a supply reel, a film and a strip of noncombustible material wound spirally on said supply reel so that substantially all portions of the surfaces of said film are in contact with said strip of non-combustible material, a motor of the reversing type for actuating said supply reel, means for unwinding said film from said supply reel, a take-off reel adapted to receive said film, a second motor for actuating said unwinding means and said take-off reel, a second strip of non-combustible material which is wound spirally on said take-off reel with said film so that substantially all portions of the surfaces of the film move into contact with said second strip of noncombustible material, means for reversing the first mentioned motor in the event portions of the film are separated by burning of the film whereby a portion of the film moves in the normal direction to be wound spirally on said takeofi reel with said second strip of non-combustible material while another portion of the film is rewound spirally on said supply reel with the firstmentioned strip of non-combustible material, a reel for receiving the first-mentioned strip of non-combustible material, and'a reel for receiving the second-mentioned strip of non-combustible material.

9. A motion picture projecting machine including a supply reel, a film and a strip of noncombustible material wound spirally on said supply reel so that substantially all portions of the surfaces of said film are in contact with said strip of non-combustible material, a motor of the reversing type for actuating said supply reel, means for unwinding said film from said supply reel, a take-off reel adapted to receive said film, a second motor for actuating said unwinding means and said take-ofi reel, a second strip of non-combustible material which is wound spirally on said take-oil reel with said film so that substantially all portions of the surfaces of the film move into contact with said second strip of non-combustible material, means for reversing the first-mentioned motor in the event portions of the film are separated by burning of the film whereby a portion of the film moves in the normal direction to be wound spirally on said take-01f reel with said second strip of non-combustible material while another portion of the film is rewound spirally on said supply reel with the first-mentioned strip of non-combustible material, and a shield adapted to move into a position where it protects the film from the direct rays of the projecting light of the projecting machine.

10. A motion picture projecting machine including a supply reel, a film and a strip of noncombustible material wound spirally on said supply reel so that substantially all portions of the surfaces of said film are in contact with said strip 0:": non-combustible material, a motor of the reversing type for actuating said supply reel, means for unwinding said film from said supply reel, a take-off reel adapted to receive said film, a second motor for actuating said unwinding means and said take-ofi reel, a second strip of non-combustible material which is wound spirally on said take-off reel with said film so that substantially all portions of the surfaces of the film move into contact with said second strip of non-combustible material, means for reversing the first mentioned motor in the event portions of the film are separated by burning of the film whereby a portion of the film moves in the normal direction to be wound spirally on said said take-01f reel with said second strip of non-combustible material while another portion of the film is rewound spirally on said supply reel with the first-mentioned strip of non-combustible material, and a shield actuated in response to stoppage of the movement of the film through the light field of the projecting machine and adapted to move into a position where it protects the film from the direct rays of the projecting light of the projecting machine.

- 11. A motion picture projecting machine including a supply reel, a film and a strip of noncombustible material wound spirally on said supply reel so that substantially all portions of the surfaces of said film are in contact with said strip of non-combustible material, a motor of the reversing type for actuating said supply reel, means for unwinding said film from said supply reel, a take-01f reel adapted to receive said film, a second motor for actuating said unwinding means and said take-off reel, a second strip of non-combustible material which is wound spirally on said takeoff reel with said film so that substantially all portions of the surfaces of the film move into contact with said second strip of non-combustible material, means for reversing the first-mentioned motor in the event portions of the film through the light field of the projecting machine are separated by burning of the film whereby a portion of the film moves in the normal direction tobe wound spirally on said take-off reel with said second strip of non-combustible material while another portion of the film is rewound spirally on said supply reel with the first-mentioned strip of non-combustible material, and a shield actuated in consonance with said motor-reversing means in response to stoppage of the movement of the film and adapted to move into a position where it protects the film from the direct rays of the projecting light of the projecting machine.

12. A motion picture projecting machine including a supply reel, a film and a strip of noncombustible material wound spirally on said supply reel so that substantially all portions of the surfaces of said film are in contact with said strip of non-combustible material, a motor of the reversing type for actuating said supply reel, means for unwinding said film from said supply reel, a take-off reel adapted to receive said film, a second motor for actuating said unwinding means and said take-01f reel, a second strip of non-combustible material which is wound spirally on said take-ofi reel with said film so that substantially all portions of the Surfaces of the film move into 4 contact with said second strip of non-combustible material, means for reversing the first-mentioned motor in the event portions of the film are separated by burning of the film whereby a portion of the film moves in the normal direction to be wound spirally on said take-ofi reel with said second strip of non-combustible material while another portion of the film is rewound spirally on said supply reel with the first-mentioned strip of non-combustible material, a reel for receiving the first-mentioned strip of non-combustible material, and a reel for receiving the second-mentioned strip of non-combustible material, said reel for receiving the first-mentioned strip of non-combustible material being driven by the motor that drives said supply reel.

JOSEPH J. SHERWOOD.

FRANK A. PEN'ILAND. 

